1. Technical Field
The present disclosure relates to networked nodes, and more specifically to neighbor lookup operations in a network node.
2. Related Art
A network node refers to either a switch or an end system. End systems are the eventual source or destination of packets, while switches forward packets to provide connectivity between end systems.
End systems are typically viewed as being connected to corresponding local networks, with switches forwarding packets between the local networks. The networks thus connected are termed as Internet, and IP (Internet Protocol) is a common networking protocol used for internetworking, as is well known in the relevant arts.
Each network node may be viewed as having at least one associated global address and a local address. For example, IP protocol provides for a unique global address for each network node connected to the Internet. Such a global address enables a corresponding packet to be routed across potentially several intermediate networks before a packet is delivered to the eventual destination end system using IP.
On the other hand, local addresses are specific to the implementation of the local networks, and are typically relevant only for delivering packets within the local network. For example, assuming a local network is implemented compatible with 802.3 Ethernet standards, the medium access control (MAC) Ethernet address specified according to the standards represents the local address.
Network nodes often are required to perform neighbor lookup operations. A neighbor lookup operation entails mapping global/IP address (already specified in a packet) to corresponding local/MAC address of a next (neighbor) network node on the same local network, to which the packet is to be forwarded. The local address thus determined is used to deliver the packet to the next network node.
As the same mapping information is potentially required for forwarding several other later packets to the same next network node, the information is maintained in a memory for supporting additional lookup operations. As a network node can forward packets to multiple neighbors, mapping information corresponding to all such neighbors may also be maintained in the memory.
It is generally desirable that the lookup operations be implemented to meet the requirements (e.g., throughput performance) of the corresponding network node. Aspects of the present disclosure facilitate such requirements to be met, at least in some environments, as described below.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.